Contralateral Reinnervation after Complete Facial Nerve Paralysis

Abstract

A 57-year old male patient had a complete left facial nerve palsy after resection of a schwannoma of the left cerebellopontine angle. Nine months after the operation the patient was able to perform a weak voluntary contraction at the left angle of his mouth. A motor nerve conduction study revealed small compound motor action potential (CMAP) with a long latency in the left orbicularis oris and mentalis muscle with stimulation of right facial nerve whereas no CMAP was recorded with stimulation of left facial nerve. The needle EMG showed polyphasic motor unit action potentials in the left orbicularis oris and mentalis muscles. Contralateral rennervation is uncommon phenomenon in clinical practice. It can be misinterpreted as an adequate regeneration of damaged nerve, and mislead the clinicians to improper management. We recommend electrodiagnostic evaluation considering the possibillity of reinnervation from the contralateral nerve in the complete facial nerve palsy.